1. Field of the Invention
The present invention provides method and apparatus for neutralizing and detoxifying organic hazardous substances comprising dibenzofuran, dibenzo-p-dioxin and its chlorides (dioxin), tetrachloroethylene, trichloroethylene (ethylene trichloride), cyan and other halogenated compounds.
2. Description of the Prior Art
As new technologies have been developed along with advancement of human beings, a vast amount of organic hazardous substances is continuously created in proportion to the degree of advancement Especially, the generation of dioxin and derivative compounds is mainly caused by incomplete combustion of a large amount of city refuse and industrial wastes in exhaust gas and ash in the incinerator. In addition, organic synthetic substances containing organic hazardous substances (for instance, pesticides, medicine, synthetic plastics, paints, and so on) are manufactured in large quantities. Further, the increase in the use of chloride family bactericides for kitchen refuse and chemicals for domestic animals is a cause of increasing hazardous substances introduced into the environment. The source of hazardous substances are solvents comprising dibenzofuran, 7,7,8,8-tetracyanodimethane, dioxane,: dichloroethyl ester (these compounds are non-protonic substances) and the group of molecules including formarine (37% formaldehyde solution used as a disinfectant), chloroform (trichloromethane, a disinfectant). Examples of organic hazardous substances are as follows:
(1) Tetrachoroethylene (Cl2Cxe2x95x90CCl2)
(2) Trichloroethylene (CHClxe2x95x90CCL2)
(3) 2,4,6-trichlorophenol (C6H3Cl3O)
(4) chlotbdibenzodioxine (=2,3,7,8-TCDD) and other 75 isomers
(5) chlorophenol (C6H5ClO)
(6) 1-chloro-2-propanol (CH2ClCH(OH)CH3)
(7) alkylhalide ((CnH2n+3)X; where X is halogen
(8) allylhalide ((CH2xe2x95x90CHCH)X; where X is halogen
(9) organometallic compound; for instance, organic semi-metal, arsenichloride (Rxe2x80x94Hg; where R is alkyl group)
A high-temperature treatment through incineration is currently known in the prior art for detoxifying these hazardous substances including dioxin.
The conventional method for the removal of organic hazardous substances that is generally being practiced today is the incineration method. However, in most cases, hazardous molecules (halogen molecules) and other various organic hazardous compounds (chloro-benzene and the like) are mixed in exhaust gas, and an extremely complex and expensive apparatus is needed for the treatment at high temperature.
The prior art has noted that all compounds in the material can be decomposed into detoxified forms when incinerating at a high temperature. However, the inventors of the present invention are unaware that this contention of possible detoxification has been verified. In addition, there is no explanation for what kind of phenomenon carries out a complete incineration process at an extremely high temperature and it is not clear how and what kind of form the organic gas turns into. For instance, if a large amount of halogen, cyanide, and methane group is released in atmosphere, the atmospheric gas will become out of balance. Also, it is assumed that when an excessive amount of chlorine combines with other molecules like ozone and hydrogen in the atmosphere, hypochlorous acid is formed, resulting in acid rain and photochemical smog. In the same manner, it is presumed that dioxin would be completely decomposed if it is incinerated at a high temperature, but chlorine atoms and molecules will never be converted into any other element.
In addition, hazardous gas (halogenated compounds, hydrocarbons, cyanide, etc.) that is released into air from the smokestack of an incineration plant can form oxalaldehyde or biformyl (OHCCHO), for instance, through recombination under the influence of ozone (O3), vapor, ultraviolet, or electromagnetic wave in the atmosphere. On the other hand, through sublimation dioxin disperses into atmosphere and binds with benzene group existing in soil, then returns to the original form of dioxin. In other words, the chance of dioxin returning in the soil is high.
Hazardous substances including organic antimony (Rxe2x80x94Sb), organic arsine (Rxe2x80x94As), organic phosphor (Rxe2x80x94P), organic mercury (Rxe2x80x94Hg), organic bismuth (Rxe2x80x94Bi) are the substances having strong magnetism and exist in a stable form in the incinerated ash. However, once they are exposed to ultraviolet, they are ionized depending on the conditions of decomposition and dissociation. Consequently, hazardous metal and alkyl gas will be generated.
The alkylated compounds as stated above will become hazardous substances through hydroxylation and halogenation reactions. As a result, these compounds can be dissolved, eluted, and widely dispersed to cause environmental pollution.
This object of the invention is to provide a simple and economical method and apparatus for removing organic hazardous substances from a variety of waste materials.
The present invention provides a method for removal, stable fixation, and detoxification of organic hazardous substances from the mixture of various waste materials in order to prevent environmental pollution.
The method for removing organic hazardous substances provided by the present invention starts from Lewis acid and base and in essence it is a chemical treatment method based on organic electron theory. Organic solvents used for (high voltage) transformers and power transmission are utilized to illustrate a representative case of organic hazardous substances treated by the method of the present invention.
The substances mixed in polar solvents (non-proton family) of the transformers comprise dioxane, dioxin (2,3,7,8-TCDD), and so on as the electron transfer complex compounds. Using the selected polar solvents in the invention, isolation and decomposition of these hazardous substances (dioxane, dioxin, and so on) is accomplished.
The processes of isolation and decomposition comprise replacement, hydrolysis, open-ring polymerization, and other reactions as well as the repetition of these reactions (continuous and simultaneous reactions).
The invention is based on the selection of the most satisfactory solvents and conditions for reaction (electrophilic replacement reaction, SE reaction) In other words, as to the physical properties of dioxin, from the standpoint of Muliken""s theory of intermolecular electron transfer, dioxin is a charge transfer complex compound as an organic hazardous compound, and a resolution step starts from the selection of a matching solvent.
From the standpoint of quantum theory, most, appropriate techniques are examined by considering physical properties and characteristics of organic hazardous substances. Moreover, the major requirements for selecting agents for the treatment are the techniques as the conditions for the reaction of substances and treatment of exhaust gas (including apparatus) as well as those for stable fixation during decomposition and after treatment are considered.
On the other hand, when selecting a solvent that is most appropriate for an organic reaction, for instance, in order to avoid a hazard like intoxication due to the inhalation of gas, temperature was considered as a requirement to prevent dispersion of hazardous substances due to vaporization.
In addition, most of the isolated molecules from organic hazardous compounds have a melting point (m.p.) and a boiling point (b.p.) in the low temperature range and basic temperature for treatment is set within such temperature range. In other words, treatment temperature (ambience) is set as the standard temperature (27-30xc2x0 C.). However, the chlorine group (m.p. xe2x88x92101.04xc2x0 C., b.p. 34.1xc2x0 C.) and cyanide group are recovered completely in a reaction furnace, where dual safety measures, including solvent handling procedure and an exhaust gas absorption device, especially as their physical properties are provided.
The removal work, in accordance with the teachings of the invention, (treatment with solvents) of organic hazardous substances is carried out by setting an upper temperature limit of 30xc2x0 C. Therefore, the reactions of all reactants (including catalysts) are carried out in a solution so that the elevation of temperature is suppressed.
The present invention selects solvents depending on the physical properties, characteristics, and molecular structure of organic hazardous substances and to neutralize and detoxify them based on the treatment at room temperature or below.
Regardless of what the organic substances are, the solvents to neutralize and detoxify organic hazardous substances are selected so as to utilize chemical reaction with such selected solvents. The following catalysts and reactants are selected:
1. Nitrous ester: molecular formula Rxe2x80x94ONO (R: alkyl group) or sodium nitrite: molecular formula NaNO2 (Solution 1)
2. Sodium 1-naphthylamine-4-sulfonate: molecular formula; C10H8(NH2)SO3Na (Solution 2)
3. 2-naphtol-4-sulfonic acid: molecular formula; C10H804S (Solution 3)
4. The isomer of compound in 3 (Solution 4)
5. Graphite (black lead) (Adsorbent 5)
6. Calcium oxide or (powdered) calcium hydroxide: molecular formula; CaO and Ca(OH)2 (Adsorbent 6)
7. Terpene as an unsaturated hydrocarbon group (compounds having an isopropyl group; (CH3)2CHxe2x80x94). The reagents used in the embodiment is alpha terpineol, CAS [2438-12-1], molecular formula C10H180. (Solvent 7)
The present invention thus provides a unique, effective, and economical method for the removal of organic hazardous substances (dioxin) that are contained in the solvents used for transformers from the polluted soil or landfill soil due to illegal dumping.